At the present time, there are commercially available various configurations of blind fasteners for securing or clamping a plurality of members together to a preselected controlled tightness by assuring that the fastener is driven to the desired tightness by causing the rotatable element to fracture when a predetermined stress or load is achieved during the installation of the blind fastener. The type of blind fasteners under consideration generally are all provided with a weakened portion, formed by a V-shaped groove or the like, to respond to the rotatating forces applied to the rotatable element of the fastener during installation so as to cause the fastener to contract until it fractures at the V-shaped groove at the preselected tighteness, at which time the elements of the fastener are in clamping engagement with the members to be secured and at predetermined stress or load controlled by the fracture of the fastener. Various configurations of installation tools are commercially available for installing these types of blind fasteners. The installation tools have different types of power sources that may range from pneumatic to manual sources while some are configured in accordance with the limited space available for access to the fastener for installation purposes. At the present time each type of installation tool comprises a preselected type of a driver with unique adapter elements configured to accommodate the type of blind fastener to be installed and the configuration of the drive element of the installation tool. The adapter elements presently consist of a single nose adapter and a single wrench adapter. The nose adapter is configured to hold the head element or drive nut of the blind fastener stationary during installation of the blind fastener. The wrench adapter is configured to rotate the screw or core bolt of the blind fastener to be coupled to the rotary drive element of the installation tool for rotating the core bolt during installation of the blind fastener.
The adapter elements are used together and are mounted to an installation tool for engaging the nose adapter element with one element of the blind fastener for maintaining it stationary and to rotate another element of the blind fastener relative thereto by the wrench adaptor to provide the desired clamping of the members of the blind fastener and thereby the members to be clamped or secured together. The problem of present day adapters is that for a given size range of fastener, an adapter assembly will be useful with only one type of installation tool--it is "dedicated", i.e., an adapter assembly useful with a pneumatic type of installation tool cannot be used on a hand powered tool and vice versa, thereby requiring a large number of wrench adapters. Similarly, the nose adapters are unique to a blind fastener.
The type of blind fasteners under consideration for the purposes of the present invention have been developed over a period of some 34 years and are particularly useful in aerospace applications and are well known in the art. The blind fasteners are commercially available from various fastener manufacturers and are identified under the trademarks "Jo-Bolt", "Visu-Lok", "Visu-Lok II", "Composi-Lok", "Composi-Lok II" and "Comp-Tite". The "JoBolt", "Visu-Lok" and "Composi-Lok" family of blind fasteners are available from Monogram Industries and Voi-Sham Industries of Los Angeles, California, while the "Comp-Tite" type of fastener is available from SPS Technologies of Jenkintown, Pa. The "Visu-Lok" type of blind fastener is disclosed in U.S. Pat. No. 3,643,544. A "Composi-Lok" type of blind fastener is disclosed in U.S. Pat. No. 4,457,652. These blind fasteners have been developed for securing metallic members together and/or materials that are relatively soft, such as certain composite materials. These types of blind fasteners generally comprise a drive nut or fastener head to be maintained stationary during installation of the drive fastener and a screw or core bolt adapted to be rotated during installation. The screw or core bolt is provided with a weakened section that is responsive to the rotational torque applied thereto during installation so as to fracture at a preselected stress or load when the fastener elements are being installed. The installation procedure causes the contraction of the fastener clamping elements to cause the nut or head element to be placed into clamping engagement with one of the members to be secured and to place the clamping member carried by the rotatable or screw element into clamping engagement with the other member to be secured. The nut or fastener head and the screw or bolt are accessible from the same side of the blind fastener (the non blind side) or one side of the members to be secured so as to permit operation thereon by an installation tool. When the desired tightness of the fastener elements is achieved and thereby the desired tightness for the members to be clamped together or secured, the core bolt is designed to fracture to assure that the desired tightness has been achieved at the fastener and thereby the members clamped under the desired stress.
When considering the tooling and more specifically the adapter elements used with the installation tools for such blind fasteners, for any given size of fastener, the style of the nut or head element must be considered in order that the nose adapters may be properly coupled to the head for maintaining it in a relatively stationary position during the installation thereof. These heads have various styles and therefore require an individual nose adapter that is configured to be coupled to the head configuration for the particular type of blind fastener to be installed. In the use of the aforementioned types of blind fasteners, the various head styles that are presently in use include a flush head for the Jo-Bolt, Visu-Lok and Composi-Lok types of fastener. A protruding hexagonal head style is used on the Jo-Bolt fastener, and a millable head is found on a Jo-Bolt fastener wherein the protruding portion of the head can be milled off after the fastener is locked in place. A reduced flush type of head is used on the Jo-Bolt, Visu-Lok and Composi-Lok types of fastener. The blind fasteners that have been developed for fastening the composites such as the Visu-Lok II and Composi-Lok II utilize an additional component for installation, namely, a drive nut having a desired configuration such as a 12 point drive nut. Accordingly, one end of the conventional nose adapters must be configured to be coupled to the head style of the blind fastener selected for use in any particular fastening application. The other end of the nose adapter is constructed and defined to be secured to the installation tool conventionally by being threaded thereto for maintaining the head in a stationary position during installation of the fastener.
Various types of installation tools are presently available for use with the aforementioned types of blind fastener. The installation tools may be pneumatically powered or hand powered or have various configurations to accommodate the available space at the location of the members to be secured together for locating the tool and operating on the blind fastener. Typical blind fastener tools are known in the art and two such tools are disclosed in U.S. Pat. Nos. 2,789,597 and 3,128,655. These patents disclose the method of use of the prior art type of installation tools for blind fasteners of their time. Various other types of installation tools are commercially available, including those from Lok-Fast, Inc. of 864 West 16th Street, Newport Beach, Calif. 92663. Lok-Fast, Inc. supplies the types of installation tools required for the type of blind fasteners under consideration for the purposes of this invention and the installation tools are the typical tools that are identified by Lok-Fast, Inc., as pistol grip, torque responsive pneumatic tools, pneumatic right angle tools, close quarter tools and hand ratchet type tools. The pistol grip tools, for example, are useful with blind fasteners sold under the trademarks "Visu-Lok", "Composi-Lok", and "Comp-Tite", and similar right-angle pneumatic drivers are available for use with the same series of blind fasteners. Also, right angle, pneumatic standard drivers are characterized for use with this family of blind fasteners. In addition, a right angle, pneumatic close quarter driver, a ratchet hand tool driver and a close quarter ratchet hand tool driver is available from Lok-Fast, Inc. for use with the Visu-Lok, Composi-Lok and Comp-Tite family of fasteners. As indicated hereinabove, the installation tools of the prior art must be utilized with the desired adapter elements that are dedicated for use with the type of installation tool. Accordingly, the wrench adapter of the adapter system for such prior art tools is configured to be rotatably coupled to the output rotatable element of a unique type of installation tool. Since each of these installation tools has a different type of rotatable element, the wrench adapter must be configured to be readily rotatably coupled to such a driving element for the installation tool and its opposite end coupled to the screw or core bolt element of the blind fastener. The prior art adapter assemblies are presently constructed and defined so that the wrench adapter is sized to be mounted inside the nose adapter when it is coupled to the rotatable element of the installation tool with the nose adapters secured in a stationary relationship with the installation tool for installation operations.
Accordingly, it should be evident that the present state of the art is that for each given size blind fastener each of the various styles of blind fasteners available and the various types of installation tools available , must be considered in order that the correct adapter assemblies for the installation tools and the blind fasteners may be properly assembled for installing the selected blind fastener. This results in the requirement for the relatively large number of nose adapters and wrench adapters in the present methods of installing the blind fasteners under consideration. It has been determined that to install the JoBolt, Visu-Lok, and Composi-Lok family of fasteners that are manufactured by Monogram and Voi-Shan Industries, for example, it is necessary to presently provide approximately 318 nose adapters and approximately 61 wrench adapters. Accordingly, in order to install one of these types of blind fasteners, a nose adapter that is useable with a particular head style and a wrench adapter that is useful with a particular type of installation tool must be resorted to, and numerous nose adapters and wrench adapters that are not useful must be culled through and set aside, Tool component selection for driving any particular type and size of blind fastener is therefore made difficult and time-consuming. This results in the requirement for the relatively large number of nose adapters and wrench adapters in the present methods of installing the blind fasteners under consideration.
Some blind fasteners of the type under consideration have also been modified to add an additional component thereto, namely, a drive nut. These drive nut fasteners have been identified in the trade by the trademarks "Visu-Lok II" and "Composi-Lok II". The use of these types of "drive nut" fasteners has resulted in the simplification of the installation tools in that only two nose adapters are required for the installation of these types having 5/32" to 3/8" diameters. A separate wrench adapter is still required for each diameter fastener in both of the Visu-Lok II and Compsi-Lok II drive nut type blind fasteners. However, the drive nut type blind fasteners are only used for fastening composite structures and not metal structures, so that the partial simplification of tooling enabled by the drive nut fasteners is only applicable in a very limited, specialized situation.